The following is a chapter from the book Mega Brain, by Michael Hutchison. Mr. Hutchison also has another book, The Book of Floating which is totally dedicated to the float tank.  



Although modern flotation tanks make use of sophisticated technology, the way they work is quite simple. Essentially, the tank is an enclosed container about the size of a closet turned on its side. The vessel contains a shallow pool of warm water (about 13 inches) in which over eleven hundred pounds of Epsom salts have been dissolved, creating a solution so dense - far more buoyant than the Dead Sea or Great Salt Lake - that anyone who lies back in the water bobs on the surface like a cork. When the door is closed, the tank is totally dark. This complete absence of external visual stimulation is something most of us never experience in ordinary life situations, since even in the darkest rooms, or on the darkest of nights, with our eyes tightly closed, we still receive some ambient light. In the tank, it is impossible to tell whether your eyes are open or closed. Immediately, that is, you are in a visual blank-out.

Since your ears are underwater and stopped with plugs, there is also an almost total absence of external sounds, another experience with no counterpart in ordinary life situations. With this turning off of both sight and sound, the float tank matches the blank-out effect created by the unchanging ganzfeld and pink noise of the Tranquillity. However, the tank goes beyond this by restricting stimuli reaching other senses as well. The warm water of the tank is maintained at a constant temperature of about 93.8 degrees, which is equal to the body's temperature at the skin surface - there is no feeling of either warmth or cold, so that you soon lose any sense of separation between skin and water, and the boundaries of your body seem to dissolve, effectively creating a blank-out of the sense of touch, pressure, friction, and other skin sensations.

Another sensation floating turns off is the usually ever-present pressure of gravity. In the words of the tank's inventor, neurophysiologist Dr. John Lilly, "You're free of gravity; you don't have any more of those gravity confrontations that you do all day long. Finding where gravity is, and in what direction, and computing how you can move and not fall takes up about 90 percent of your neural activity. As soon as you start floating you're freed of all the gravity computations you've been doing all the time, so you find you have a whole vast piece of machinery that was being used for something else and you can now use it for your own purposes... It's as if you are somewhere between the moon and the earth, floating, and there is no pull on you. As soon as you move, of course, you know where you are, but if you don't move your environment disappears and, in fact, your body can disappear."

The tank, then uses technological means to quickly, easily, reliably, and safely produce the turning off of the senses that all the meditative techniques such as breath-counting, chanting, repetition of mantras, and focused gazing strive for but so rarely attain. Even first-time floaters find that within minutes they are suspended weightlessly, without a body, in a totally black, silent void.

And unlike meditative techniques, which are so numerous and have so many variables that it is difficult to subject them to large-scale, objective, controlled, repeatable scientific studies, the flotation tank is a controlled and unchanging environment, ideally suited for scientific research. Attempts to study meditation often must compare groups of subjects engaged in specific meditative techniques with control groups who are (usually) simply sitting quietly. But as we have seen, it is often hard to tell if meditators are truly in an authentic meditative state. However, when using the tank, there can be no doubts which group is floating and which is not. The result is that float-tank research produces those things so dear to the scientific heart-hard data, value-free statistics, replicable objective studies. As a consequence, there has been a surge of flotation-tank research in recent years by large numbers of scientists interested in the workings of the human mind, including cognitive psychologists, neuroendocrinologists, educators, and psychiatrists. These researchers have produced a comparatively large body of information about the effects of flotation and sensory deprivation. Among their findings:


Events which disturb our body's natural equilibrium or homeostasis are stressful, and as we've noted earlier, stress impairs our ability to think clearly. One study of schoolchildren cited above shows that children suffering stress scored 15 percent lower on IQ tests than children experiencing low stress. Elevated blood pressure also clearly lowers mental performance. Other studies have demonstrated that stress causes dramatic reductions in ability to think coherently or creatively, and to perform movements requiring skill and dexterity.

So it's of enormous importance that a large amount of research, particularly several series of studies at the Medical College of Ohio, Lawrence College, St. Elizabeth's Hospital in Appleton, Wisconsin, and the University of British Columbia, demonstrate that floating has a dramatic stress- reduction effect. Among the findings are that periodic floats reduce heart rate, oxygen consumption, and the levels of stress-related biochemicals in the bloodstream, including cortisol, ACTH, lactate, and adrenaline. The studies show that floating not only reduces these biochemicals during the float period, but also keeps the levels low for days and in some cases weeks after the float session. Because of an apparent vasodilatory effect (that is, blood vessels and capillaries are caused to relax and dilate), floating not only reduces high blood pressure but speeds and increases the flow of blood, with its oxygen and other nutrients, to all parts of the brain. We can speculate that this increased flow of blood to the brain enhances mental functioning and assists in building new brain tissue and nourishing neurons, leading to greater dendritic length, increased richness of dendritic connections, and increased thickness and weight of the neocortex. An enriched flow of blood is essential to protein synthesis, and since recent findings by neuroscientists have shown that memory formation is dependent on protein synthesis in the brain, we can also speculate that this blood-enrichment effect of floating enhances memory formation.


All of us are able to withstand or resist certain levels of stress, but for each of us the level at which stress becomes disruptive is different. In the words of Yale biochemist Philip Applewhite, "The hypothalamus brain program that recognizes stress when it comes in over the nerves is certainly a source of variability. Some people may feel stressed when not much has happened to them; they have a low tolerance for stress. For others it may take considerably more stress before the hypothalamus identifies it as such; these people have a high tolerance for stress." That is, the hypothalamus acts as a homeostatic mechanism, acting to help the body maintain its equilibrium in the face of external stress. Some people's homeostatic mechanism is much more sensitive to stress, that is, some people's homeostatic mechanism has what is called a lower "set point."

In light of this, it's significant that studies by neuroendocrinologist John Turner and psychologist Tom Fine at the Medical College of Ohio indicate that floating not only significantly reduces the levels of stress-related biochemicals, but also has what Turner and Fine call a strong "maintenance effect" - the lowering of the stress biochemicals continued for many days after the subject's last float. This has led them to conclude that floating can "alter the set points in the endocrine homeostatic mechanism so that the individual would be experiencing a lower adrenal activation state. It would essentially be associated with a greater degree of relaxation".

This is striking, since it means that the beneficial effects of floating are not just temporary, but alter the metabolism (or homeostatic set point), essentially damping down the fight-or-flight response. This means that levels of pressure that might once have disrupted your ability to think clearly and perform effectively will seem less stressful after floating. That is, floating is a way of increasing our tolerance for stress.


We all know instinctively that peak mental performance flows from relaxation, since our descriptions of peak moments of mental clarity and creative flashes emphasize effortlessness, fluidity: problems that we have strained over for months suddenly resolve themselves in a moment of release, and we say, "Why didn't I see it before - it's so easy!" By comparison, those who are mentally struggling are a study in muscular tension - they writhe in their chairs, grimacing, contorted. Also, as we've seen, studies of "twilight learning" or "Superlearning" show that we are best able to assimilate new information and think clearly when we're relaxed.

But good relaxation is hard to find. Relaxation techniques such as Progressive relaxation, Autogenics, and meditation take effort and discipline, with no assurance of success. In fact, many authorities now believe that most of us have never experienced complete relaxation in our lives, so we have no real conception of what it feels like, and no idea of how to cause our bodies to create that state.

In the warm Epsom salts of the float tank, however, free from the tug of gravity, your muscles unfold like Chinese Paper flowers in water, growing supple and pliant. Several studies have used an electromyograph (EMG), which measures muscular tension, to compare groups who simply floated with groups of nonfloaters who relaxed by using various relaxation techniques. In every study floaters quickly became far more deeply relaxed than the nonfloat groups. Significantly, this reduction in tension persisted, according to one study, for up to three weeks after a float.

In fact, all evidence indicates that floating actively and automatically triggers the mirror image of the fight-or-flight response, the relaxation response. This reflexive response includes reductions in heart rate, blood pressure, alterations in brain-wave, muscular relaxation, decreased oxygen consumption, decrease in stress-related biochemicals, and increased secretions of biochemicals that fill the body with a sense of well-being, pleasure, safety, and mental clarity. If the fight-or-flight response is one of spending energy and acting, the relaxation response is one of saving energy and thinking. Research indicates that floating activates this healthful response effortlessly. According to Fine and Turner of the Medical College of Ohio: "These (other relaxation) techniques have the individual elicit relaxation utilizing some internal strategy with or without external feedback as to the success of the strategy. In contrast (floatation tank) relaxation utilizes an environment to induce relaxation with the individual passively experiencing the process... The controlled repeated experiences of this effortless passive relaxation provided by the tank may provide an advantage over these other methods requiring a trial and error approach to the deep relaxation state."


In their continuing inquiries into the psychobiological effects of floating, Fine and Turner found that a session in the tank dramatically reduced pain and often induced a feeling of mild euphoria. They experimented further, using subjects who suffered from severe chronic pain. The results were exciting. Fine told me that "virtually all of our chronic pain patients have said that during the flotation period they have lost awareness of their pain." Wondering what this pain-relief mechanism might be, they set up a double-blind experiment in which one group received the endorphin antagonist naloxone. The other group received only a placebo, The study showed that 100 percent of the subjects were able to tell whether they had received the endorphin blocker or not. The implications are that floating stimulates the body to release endorphins, and that the increased levels of endorphins caused by floating are the cause of the pain reduction and feelings of euphoria. As we have seen earlier, endorphins are intimately related with a variety of brain-mind functions, including memory and learning. It's possible that by stimulating our natural reward systems, increased endorphin levels might assist in putting floaters into an ideal state for learning.


Partially as a result of the deep relaxation floating induces, floaters experience an increased production of theta waves. One study by Gary S. Stem of the University of Colorado at Denver found that "the significant effect of floating ... indicates that individuals who had floated in the isolation tank for one hour significantly raised their theta level." The intriguing and mysterious theta state, on the threshold between the conscious and the unconscious, is characterized by vivid, unpredictable imagery, spontaneous memories, Eureka moments when creative ideas and solutions to problems appear suddenly, and feelings of serenity, euphoria, and peace. It is also, as indicated by studies such as those of biofeedback expert Thomas Budzynski of the University of Colorado Medical Center, a "twilight" state when the brain "has these properties of uncritical acceptance of verbal material, or almost any material it can process. What if you could cause a person to sustain that state, and not fall asleep?" asks Budzynski. "I believe flotation tanks are an ideal medium for doing that."


Research also indicates that floating increases the power of, or increases the floater's access to, the right brain. Thomas Budzynski, who is engaged in EEG measurement of the hemispheres under varying conditions, asserts "In a float condition, left hemisphere faculties are somewhat suspended and the right hemisphere ascends in dominance." Or, Budzynski says more bluntly, "The right brain comes out in that float tank and says 'Whoopee!'" Budzynski , with many other brain researchers, believes that this increased access to the right hemisphere can lead to enhanced learning abilities. Says Budzynski, "Get access to the right hemispheres of individuals very quickly, and keep them in that state, and that's where a lot of work gets done very quickly. We get at this same place with float techniques, 'twilight learning,' subliminal processing, hypnosis, all of these."


There is now overwhelming evidence that floating enormously increases suggestibility; that is, whatever information you receive while in the tank, whether in the form of suggestions made silently to yourself or as audio or visual information presented to you while floating, is accepted fully. In part, this is due to the altered brain-wave states mentioned above - increased theta, greater direct access to the right hemisphere, and hemispheric synchronization.

Another explanation is the "stimulus hunger" effect - in the absence of external stimulation, the RAS "turns up" the brain's volume control and the brain becomes '"hungry" for information. So when it's given a message, it accepts it totally. Another explanation is that the part of the brain in charge of reality testing, critically evaluating incoming information, is turned off in the restricted stimulation environment of the tank, so messages can bypass the usual censor of filter and enter directly into the subconscious. In fact, Dr. Lloyd Glauberman, a New York City therapist with many years of experience in the use of hypnosis, who is now using float tanks equipped with in-tank speakers for training athletes and altering behavior patterns, told me that "the float tank is much more powerful than hypnosis - simply floating, without inducing a trance, makes you more suggestible than hypnosis." Studies at the University of British Columbia and elsewhere indicate that these in-tank suggestions have a unique "maintenance effect," retaining their power for months and, in several studies, years.


Scientists estimate that well over 90 percent of the brain's energy is expended processing external stimuli - visual and tactile information, gravitational forces, and so on. Freed in the tank of external responsibilities, the mind turns inward, and subtle mental processes which are ordinarily drowned out in the clamor of external stimuli gain remarkable force and clarity. One of these is internal imagery.

The ability to create and manipulate internal imagery, called visualization, is one of the most powerful learning techniques at our disposal, increasing our ability to solve problems by "seeing" them in a new way, increasing our ability to remember by associating nonvisual information with visual cues, and, perhaps most important, enabling us to vividly rehearse or experience events mentally. Many studies have shown that an image held vividly in the mind tends to be perceived by the subconscious and the body as being real. Visualizing yourself skillfully performing some action, whether delivering a speech, hitting a perfect tennis backhand, or solving some problem, can be as effective as actually performing the action. The problem is that most of us find it hard to visualize performing a feat with the kind of total concentration and clarity necessary to convince our body it's a happening.

In the tank, however, you are free from all distractions and light. According to Dr. Glauberman, "Your ability to visualize is much more powerful while you're floating than it is even in hypnotic ice. Imagery seems more real, more dreamlike. Most of the time you're actually in the experience."

Dr. Rod Borrie, a New York City cognitive therapist who guides his clients through in-tank visualizations to help them increase learning, improve athletic and work performance, and change behavior patterns such as smoking and overeating, explains the effect in terms of information theory "The brain," he says, "can process only about seven bits of information at one time. Complex movements, such as athletic movements, are made of far more than seven bits of information at a time. Visualization puts all those bits in one chunk, like putting together a bunch of random letters, which would be impossible to remember, so they form a single word, which can be easily remembered. While floating, you put many actions together into a total image, so when the time comes to actually perform, the entire action is 'remembered' as a single image."

Just how real this "memory" can be is attested to by javelin thrower David Schmeltzer of the New York Pioneer Track Club, who uses in-tank visualization to "watch" himself throwing perfectly. Recently he surpassed his personal record by several feet, and recalls, "When I released the javelin on that day it was like deja' vu. At the point of release, I said, 'I know this throw, I've thrown this throw before!'"

The power of previsualization is not limited to relatively short actions, but can be used to rehearse mentally or "program" yourself for enormously complex situations with virtually infinite variables. For example, Bob Said, a former Grand Prix sports-car champion, who has led two Olympic bobsled teams and five U.S. World bobsled teams, described to me how he clearly visualized every foot of the bobsled run as he floated each morning while training for the 1984 Winter Olympic trials. "In the sled," he said, "you know where you want to be in each corner but often you find yourself someplace else. So you try to visualize all the different ways you can get into each corner, so that when you get into the corner you're already programmed for coming out." In sports, as in many life situations, we need to act rapidly, almost automatically. But too often we're paralyzed by the need to stop and think. For Said, the "muscle memory" that comes from repeated visualization frees him from that need: "If you have to think a reaction in the sled, even if you have the world's fastest reactions, you're too slow. The 'cleaner' you are, the faster you are. I'm definitely sharper from floating, but it's not a sharpening of abilities so much as it's allowing one's abilities to function the way they're supposed to, by getting rid of the clutter."

According to Borrie, who has worked with Glauberman in training a number of top-flight athletes by using in-tank visualization, "Every athlete we're working with who has competed has set a personal record. And they keep on setting them. It's just a very, very powerful tool." "Phenomenal," agrees Glauberman, "and it hasn't even begun to be tapped yet." They both emphasize that such learning through visualization is not limited to athletic performance - mental rehearsals like those of Said can be equally effective in complex situations such as performing surgery, giving a speech or presentation, or performing a role in a play or ballet.


The close relationship between learning and visualization is pointed out by a recent large-scale, rigorously controlled study at Texas A&M, where chemistry professor Thomas Taylor tested two groups on their ability to learn and think. One group listened to specific lessons while relaxed in a dark room, the other while in the tank. Afterward, the groups were hooked up to an EEG and tested on how much they had learned. The learning was evaluated on three levels of increasing difficulty: simple memory or rote learning; the ability to apply the information to new situations and problems; and "synthesis thinking," the ability to combine the ideas learned in new and creative ways.

The results were startling. The float group learned significantly more than the nonfloat group on every level; but most important, as the degree of difficulty and complexity of the learning task increased, the superiority of floaters over nonfloaters increased sharply. Concluded Taylor, "There's no question that the [float] group learned more, but where they learned is the most important point. People who floated learned at a different cognitive level. The results show that the more difficult the concept, the bigger the difference in the performance of the two groups."

Interestingly, Taylor had tested the subject groups to see which were "visualizers" and which were "verbalizers," and concluded: "When the same learning records are analyzed on the basis of persons who are basically "visualizers" versus those who are primarily "conceptualizers" (nonvisual thinker), a greater degree of learning occurred in the visual than in the nonvisual group." While the number of visualizers in both groups was equal, Taylor noted that the float group appeared to visualize better than the nonfloat group. The EEGs indicated that the float group also produced significantly higher amounts of theta waves, which are associated with strong mental imagery. In summary, visualization enhances learning at all levels, floating increases visualization, floating's enhancement of ability increases as the complexity and difficulty of the material being learned increases, and floating sharply increases the ability to think creatively and synthetically. Floating seems to enhance mental functioning and open pathways of interaction between mind and body in so many ways that researcher Tom Fine of the Medical College of Ohio has called it "a breakthrough tool in psychobiology."


Studies like the one at Texas A&M have convinced many scientists and educators that the tank can be a potentially revolutionary tool for accelerated learning, and tanks are now being used for that purpose at schools, universities, and over 250 float centers throughout the US, Canada, Europe, and Japan. As research and popular use increase, it's becoming clear that the float tank can be used to enhance learning in a number of ways.


The most obvious method of using the tank is to profit from the deep relaxation, increased theta waves, heightened suggestibility, and increased ability to process information induced by floating and present the floater with the information to be learned while he or she is actually in the tank. This can be done with simple self-suggestion or visualization, the user choosing appropriate messages and images much as is done in ordinary self-hypnosis. Virtually all float tanks being produced today are equipped with in-tank speakers, so that floaters can record the information they wish to acquire on an audio tape to be played to them while they float. Users have reported excellent results in learning everything from new languages to prepping for law, medical, and real estate exams. Language students, for example, have reported that they are able to acquire several hundred new words in a single one-hour session, with a retention rate of almost 100 percent.

Most tank manufacturers now sell tanks with video monitors attached, so that floaters can relax until they are in a suitably receptive state, then turn on color videocassettes of visual material to be learned. Most commonly used thus far are commercially produced tapes of professional athletes playing at the peak of their form, demonstrating sports that include golf, tennis, running, downhill and cross-country skiing, racquetball, auto racing, soccer, baseball, basketball, football, sailing, and bowling. In a golf or tennis tape, for example, each type of swing is reproduced dozens of times for repetitive visual and sensory stimulation. The images are enhanced by sound - the solid sound of the club or racquet hitting the "sweet spot" - and computer-enhanced sequences that electronically highlight the flowing physical movements. Float-tank research at Stanford University indicates that watching such perfect performances has a "modeling" effect, causing you to absorb the movements in what has been called muscle memory programming, so that when you climb out of the tank the actual feel of the movements has been assimilated by your body. Watching a one-hour cassette is thought to be the equivalent of many hours of ideal physical practice.

Many athletes have made their own tapes. Professional football player Rafael Septien, a field- goal kicker for the Dallas Cowboys, is one example. Each day he climbs into the tank and watches images of himself kicking field goals. He credits this use of floating with helping him become an All-Pro kicker. "There's no doubt the tank is powerful," he told me. "They say that practice makes perfect, but actually it's perfect practice makes perfect. That's what you visualize in the tank - perfect practice." Other tapes have used the modeling effect to help train surgeons, musicians, salespeople, performers, visual artists, teachers, scientists, and business executives - whatever can be presented visually can be effectively presented to a floating learner. Says one maker of such training tapes, "Through recent advances in the neurological sciences, computerization, and solid- state sensing devices it is now possible to electronically transfer skills encoded on video software to the human nervous system." The possibilities of combining sight and sound seem virtually limitless and are only beginning to be explored.


One of the most widely noticed effects of floating is a feeling of mild euphoria, mental clarity, and sensory acuity that lasts many hours, even days, after leaving the tank. The euphoria can be explained by the continuing deep relaxation and the increased flow of endorphins and perhaps other peptides. The mental clarity is largely due to the alteration in brain waves - slower frequency, higher amplitude, more hemispheric synchronization - that studies indicate also continues long after emerging from the tank. The sensory acuity - floaters speak of finding colors brighter, richer, more saturated, of seeing more sharply, hearing more clearly, having intensified senses of touch and smell - seems to come from having allowed the senses to take a short vacation. They return to the world refreshed, having been what psychologist Arthur Deikman calls "deautomatized" with their doors of perception cleansed. As an example of how floating can sharpen the senses, consider recent research indicating that after only one minute of total darkness the eye's sensitivity to light increases ten times: after just twenty minutes it increases six thousand times: and after forty minutes - less time than most people spend in a flotation session - the eye reaches its limit of sensitivity to light, becoming about 25,000 times more sensitive than before the exposure to the darkness.

This enhancement of mental and physical functioning makes the hours after a float ideal for learning of all sorts, since the mind is extremely receptive to external information, yet still in a somewhat free-floating state that is conducive to imaginative and creative thinking. Many floaters find that it is in the hours after a float that they find themselves discovering solutions to problems or being seized with new ideas, and often notice that this is a time when reading, studying, listening to music, and so on are particularly rewarding and productive.


While I was interviewing floaters, one man mentioned to me a "strange experience" he had while learning Dutch. On one occasion he went in for a float immediately after his lesson. For various reasons he didn't have any time in the next few days to review the lesson, but when he went in for his next lesson, he found that he had virtually total recall of the last lesson, and his instructor remarked that he must have studied very hard in the interim. He felt that somehow the float had subconsciously solidified the information in his brain. Was this possible? he wondered.

Shortly after that I was reading some reports of sensory-restriction research and read of a study in the early 1960s in which researchers read a lengthy passage from Tolstoy's War and Peace to two groups of subjects. They did not tell the subjects to remember this passage: in fact, it was just one of a number of events that occurred prior to the experiment. The subjects did not expect a retest. One group was a control group, and went about its normal activities: the other group spent a period in a sensory-restriction chamber. After twenty-four hours the two groups were retested. The researchers found that while there was a significant drop in retention for the control group, there was none for the experimental subjects. In fact, the sensory-deprivation group remembered more after twenty-four hours than at first! In interviewing the subjects, the researchers found that none of them had expected a retest, and only one had reported that he had even thought about the passage from War and Peace during the interim. The researchers dubbed this the "reminiscence effect." Somehow, simply being in a state of sensory restriction caused an increase in memory.

A recent series of experiments has cast some more light on this curious reminiscence effect. Subjects were given information, then one group consumed several ounces of alcohol - not enough to cause inebriation, but enough to put the subjects into a relaxed and somewhat euphoric state. The control group consumed no alcohol. When the two groups were later retested, it was found that the alcohol group had significantly greater recall of the information.

How to explain? Well, scientists now agree that there are at least two types of memory, generally known as short-term memory (STM) and long-term memory (LTM). When we are aware while driving of how many cars are behind us and how close they are, this is information being held in STM - ten miles down the road we will have forgotten it. When we look up a phone number and hold it in our minds for a few moments required to make the call, this too is the STM at work. STM, in short, deals with information we need to hold in our minds temporarily, but which is quickly forgotten. On the other hand, there is another type of information that can be held in consciousness just as fleetingly as, say, that telephone number, but can become so permanent that it can be recalled with absolute clarity a lifetime later, such as the memory of some brief event observed momentarily by a child but remembered ninety years later. This is information that has passed into LTM.

Studies using drugs that inhibit protein synthesis in the brain have proved that short-acting electrochemical changes in the brain represent STM while protein synthesis in the brain is necessary for LTM. When drugs that inhibit protein synthesis in the brain are given soon after subjects learn something, the information is forgotten - that is, it never makes it into LTM. However, when the drugs that inhibit protein synthesis are given more than an hour after the learning, the information is not forgotten, which means it has become a part of LTM. In other words, information passes in LTM- protein synthesis takes place in the brain - during the hour or two after the information is received.

One type of protein synthesis in the brain is structural growth: the growth of neurons, increasing numbers of glial cells, lengthening of dendrites, formation of new dendritic spines and synapses. As we have seen, this type of protein synthesis was first detected by Mark Rosenzweig, Marian Diamond, and their colleagues at UC Berkeley. They found that rats exposed to enriched environments exhibited heavier and thicker cortical layers, composed of larger neurons, more glial cells, longer dendrites, and more dendritic connections. Later studies have shown that even a few minutes of environmental enrichment are sufficient to cause permanent brain growth: that is, a brief experience of stimulation can result in protein synthesis. A study by William Greenough of the University of Illinois have shown that rats trained to run a maze show dendritic growth immediately after the training. That is, brain growth is specific response to learning.

Learning and long-term memory can occur only when protein synthesis takes place in the brain. Protein synthesis in the brain is a direct result of learning. That is, brain growth facilitates learning and memory on the one hand, and learning and memory lead to brain growth on the other hand. Memory and learning, in other words, cannot be separated from physical brain changes. Rosenzweig and colleagues proved that environmental enrichment leads to physical brain growth and increased memory and learning. Now we see that physical brain growth is essentially identical with the process of learning and increasing memory stores. To use Prigogine's terms, as energy enters the system in the form of new information or experiences, it can only be incorporated by means of actual change in the structure and organization of the system, that is, by brain growth. If something happens to stop this brain growth, such as administering a drug to inhibit protein synthesis, the new information that has entered the system will disappear, be forgotten. However, if sufficient time is allowed for this protein synthesis to take place, permanent changes will have taken place in the brain, and the information will be a part of long-term memory.

To return to the "reminiscence effect" noted by sensory-deprivation researchers, we can surmise that this effect results from the fact that after being given the information, the sensory- restriction group was removed for a period from new sensory input, from things that would compete with the information for long-term memory: Similarly, the alcohol group remembered more because in their slightly tipsy state they turned their brains off to potential new information to be remembered, thus giving the original information sufficient time to "solidify".

It seems clear that this reminiscence effect can be put to good use by floaters. Whatever information they want to put into long-term memory should be studied immediately prior to entering the tank (or should be presented via video or audio tapes during the early part of the float). The period of sensory restriction that follows - ideally at least an hour - should allow time for the necessary protein synthesis to occur in the brain to permit the information to become consolidated and committed to long-term memory.

Also, a number of float-tank studies have made it clear that floating has a vasodilatory effect, relaxing the tiny capillaries that carry blood into and throughout the brain. This results in a greater supply of blood to the individual neurons in the brain. Since blood carries the nutrients essential for protein, increased blood flow to the brain can only enhance protein synthesis. In the words of Dr. Arnold Scheibel, professor of medicine at UCLA and an expert on brain growth, "if there is a bottom line, it is that no neuron is healthier than the capillary that supplies it. And we have a very strong feeling that in the capillary supply system is the story of the maintenance or the slow decline" of the brain. The vasodilation that takes place while you are floating, then, facilitates brain growth, which means that by increasing blood flow to the brain floating can facilitate learning and the formation of long-term memory.